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Semeste 1 2010/2011

Semeste 1 2010/2011

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  • 1. IE 20303 Technology Infrastructure for E-Commerce
    i.E Business Data Communication & Networking
    By
    MohdYuszrenYusak
    Google me up,I’m on Facebook, Twitter & I have a blog.
  • 2. First things first
    Non fiction-no vampires inside
    “examines the factors that contribute to high levels of success”
    Problems? See me ASAP!
    Tweet with me! yuszrenIE20303
    We need to see the world from a different perspective MORE often!- ie class trip anyone?
    Class starts @ 8.30am starting next week. Any objections?
    This is your ‘defining moment’ semester. Less
    fooling around please!
    Anyone interested in ‘Outliers” by Malcolm Gladwell?
    MDEC Monday Class time. I’ll stop your marketing class.
  • 3. Assessments
    Quiz-10%
    Work-10% ?(trip report?)
    2 Group Work-40% (20% each) ?
    40%-Finals
  • 4. Intro to Data Communications
    Basic concept of data
    Why important to study-the value, opportunities upon graduation. Career opportunities.
    Future trends
  • 5. Brief History
    Samuel Morse, Alex Graham Bell
    Thomas Edison- basic electrical & electronic systems evolve into voice and data communication networks.
    Read-notes.
    Why bother about history?
    Because history contributes to moral understanding.
  • 6. Career Opportunities
  • 7.
  • 8.
  • 9. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    9
    PART I Introduction and Internet Applications
  • 10. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    10
    Topics Covered
    1.1 Growth of Computer Networking
    1.2 Why Networking Seems Complex
    1.3 The Five Key Aspects of Networking
    1.4 Public and Private Parts of the Internet
    1.5 Networks, Interoperability, and Standards
    1.6 Protocol Suites and Layering Models
    1.7 How Data Passes Through Layers
    1.8 Headers and Layers
    1.9 ISO and the OSI Seven-Layer Reference Model
    1.10 The Inside Scoop
    1.11 Remainder of the Text
    1.12 Summary
  • 11. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    11
    1.1 Growth of Computer Networking
    Computer networking has grown explosively
    Since the 1970s, computer communication has changed from a research topic to an essential part of infrastructure
    Networking is used in every aspect of our lives:
    Business
    Advertising
    Production
    Shipping
    Planning
    Billing
    Accounting
    Educational institutions are using computer networks
    to provide students and teachers with access to online information
    Federal, state, and local government offices use networks
  • 12. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    12
    1.1 Growth of Computer Networking
    In short, computer networks are everywhere
    In 1980, the Internet was a research project that involved a few dozen sites
    Today, the Internet has grown into a communication system that reaches all of the world
    The advent and utility of networking has created dramatic economic shifts
    Network has made telecommuting available to individuals
    It has changed business communication
    An entire industry emerged that develops networking technologies, products, and services
    The importance of computer networks has produced a demand in all industries for people with more networking expertise
    Companies need workers to plan, acquire, install, operate, and manage the hardware and software systems for networks
  • 13. Why Research Network?
    To achieve better network robustness & disaster survivability. How?
    Packet switching technology at ARPANET = funded by the US Department of Defense (DARPA).
  • 14. use of a decentralized network with multiple paths between any two points; and second, dividing complete user messages into what he called message blocks before sending them into the network. This first allowed the elimination of single points of failure, and enabled the network to automatically and efficiently work around any failures.
    Strike 1
    The White House
    Telco
    Chicago
    Strike 2
    The Pentagon
  • 15. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    15
    1.2 Why Networking Seems Complex
    The networking subject seems complex, because
    Many technologies exist
    Each technology has features that distinguish it from the others
    Companies create commercial network products and services
    often by using technologies in new unconventional ways
    Computer networks seem complex
    because technologies can be combined and interconnected in many ways
    Computer networks can be especially confusing to a beginner because
    No single underlying theory exists that explains the relationship among all parts
    Multiple organizations have created computer networks standards
    some standards are incompatible with others
    Various organizations have attempted to define conceptual models
    The set of technologies is diverse and changes rapidly
    models are either so simplistic that they do not distinguish among details
    or so complex that they do not help simplify the subject
  • 16. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    16
    1.2 Why Networking Seems Complex
    The lack of consistency in the field has produced another challenge for beginners:
    Multiple groups each attempt to create their own terminology
    Researchers cling to scientifically precise terminology
    Marketing teams ofteninvent new terms to distinguish their products or services from others
    Technical terms are confused with the names of popular products
    Professionals sometimes use a technical term from one technology when referring to an analogous feature of another technology
    A large set of terms and acronyms that contains many synonyms
    Computer networking jargon contains terms that are often abbreviated, misused, or associated with products
  • 17. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    17
    1.3 The Five Key Aspects of Networking
    To master the complexity, it is important to gain a broad background that includes five key aspects:
    1.3.1 Network Applications and Network Programming
    1.3.2 Data Communications
    1.3.3 Packet Switching and Networking Technologies
    1.3.4 Internetworking with TCP/IP
    1.3.5 Additional Networking Concepts and Technologies
    These topics will be covered throughout the book
    In this chapter a brief introduction will be given
  • 18. 1.3.1 Network Applications and Network Programming
    Network services are provided by an application software
    an application on one computer communicates across a network with an application program running on another computer
    Network applications span a wide range, such as:
    email
    file transfer
    web browsing
    voice telephone calls (VoIP)
    distributed databases
    audio/video teleconferencing
    Each application offers a specific service with its own form of user interface
    But all applications can communicate over a single, shared network
    © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    18
  • 19. 1.3.1 Network Applications and Network Programming
    A unified underlying network that supports all applications makes a programmer's job much easier
    only programmer needs to learn about one interface to network and one basic set of functions to be used
    it is possible to understand network applications, and even possible to write code that communicates over a network, without understanding the hardware/software technologies
    once a programmer masters the interface, no further knowledge of networking may be needed
    However, knowledge of the underlying network system allows a programmer to write better code and develop more efficient applications
    © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    19
  • 20. 1.3.2 Data Communications
    Data communications refers to the study of low-level mechanisms and technologies used to send information across a physical communication medium
    such as a wire, radio wave, or light beam
    Data communications focuses on ways to use physical phenomena to transfer information
    the subject may only seem useful for engineers who design low-level transmission facilities
    However, we will see that several key concepts that arise from data communications influence the design of many protocol layers
    Data communications provides a foundation of concepts
    on which the rest of networking is built
    20
    © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
  • 21. 1.3.3 Packet Switching and Networking Technologies
    In 1960s, the packet switching concept revolutionized data communications
    Early communication networks had evolved from telegraph and telephone systems
    A physical pair of wires between two parties to form a dedicatedcircuit
    Although mechanical connection of wires was being replaced by electronic switches, but the underlying paradigm remained the same:
    form a circuit and then send information across the circuit
    Packet switching changed networking in a fundamental way
    It provided the basis for the modern Internet
    Packet switching allows multiple users to share a network
    Packet switching divides data into small blocks, called packets
    It includes an identification of the intended recipient in each packet
    Devices throughout the network each have information about how to reach each possible destination
    © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    21
  • 22. 1.3.3 Packet Switching and Networking Technologies
    Many designs for packet switching are possible
    But there is a need for answers to basic questions:
    How should a destination be identified?
    How can a sender find the identification of a destination?
    How large should a packet be?
    How can a network recognize the end of one packet?
    How can a network recognize the beginning of another packet?
    If a network is shared, then how can they coordinate to insure that each receives a fair opportunity to send?
    How can packet switching be adapted to wireless networks?
    How can network technologies be designed to meet various requirements for speed, distance, and economic cost?
    Many packet switching technologies have been created
    to meet various requirements for speed, distance, and economic cost
    © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    22
  • 23. 1.3.4 Internetworking with TCP/IP
    In the 1970s, another revolution in computer networks arose: Internet
    In 1973, Vinton Cerf and Robert Kahn observed that
    no single packet switching technology would ever satisfy all needs
    especially because it would be possible to build low-capacity technologies for homes or offices at extremely low cost
    They suggested to stop trying to find a single best solution
    Instead, explore interconnecting many packet switching technologies into a functioning whole
    They proposed a set of standards be developed for such an interconnection
    The resulting standards became known as the TCP/IP Internet Protocol Suite (usually abbreviated TCP/IP)
    The success of TCP/IP lies in its tolerance of heterogeneity
    TCP / IP takes a virtualization approach
    that defines a network-independent packet and a network-independent identification scheme
    © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    23
  • 24. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    24
    1.4 Public and Private Parts of the Internet
    The Internet consists of parts that are owned and operated by individuals or organizations
    From ownership point of view, we can categorize networks
    1.4.1 Public Networks
    1.4.2 Private Networks
    A public network is run as a service that is available to subscribers
    Any individual or corporation who pays the subscription fee can use
    A company that offers service is known as a service provider
    Public refers to the general availability of service, not to the data being transferred
    A private network is controlled by one particular group
    network use is restricted to one group
    a private network can include circuits leased from a provider
  • 25. 1.4.2 Private Network
    Network vendors generally divide private networks into four categories based on the size:
    Consumer
    Small Office / Home Office (SOHO)
    Small-to-Medium Business (SMB)
    Large Enterprise
    These categories are related to sales and marketing
    the terminology is loosely defined
    it is possible to give a qualitative description of each type
    but one cannot find an exact definition
    © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    25
  • 26. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    26
    1.5 Networks, Interoperability, and Standards
    Communication always involves at least two entities
    one that sends information and another that receives it
    All entities in a network must agree on how information will be represented and communicated
    Communication agreements involve many details
    the way that electrical signals are used to represent data
    procedures used to initiate and conduct communication,
    and the format of messages
    An important issue is interoperability
    it refers to the ability of two entities to communicate
    All communicating parties agree on details and follow the same set of rules, an exact set of specifications
    Communication protocol, network protocol, or simply protocol to refer to a specification for network communication
    A protocol specifies the details for one aspect of communication
    including actions to be taken when errors or unexpected situations arise
  • 27. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    27
    1.6 Protocol Suites and Layering Models
    A set of protocols must be constructed
    to ensure that the resulting communication system is complete and efficient
    Each protocol should handle a part of communication not handled by other protocols
    How can we guarantee that protocols work well together?
    Instead of creating each protocol in isolation, protocols are designed in complete, cooperative sets called suites or families
    Each protocol in a suite handles one aspect of networking
    The protocols in a suite cover all aspects of communication
    The entire suite is designed to allow the protocols to work together efficiently
  • 28. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    28
    1.6 Protocol Suites and Layering Models
    The fundamental abstraction used to collect protocols into a unified whole is known as a layering model
    All aspects of a communication problem can be partitioned into pieces that work together
    each piece is known as a layer
    Dividing protocols into layers helps both protocol designers and implementers manage the complexity
    to concentrate on one aspect of communication at a given time
    Figure 1.1 illustrates the concept
    by showing the layering model used with the Internet protocols
    Later chapters will help us understand layering
    by explaining protocols in detail
    For now, it is sufficient to learn the purpose of each layer and how protocols are used for communication
  • 29. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    29
    1.6 Protocol Suites and Layering Models
  • 30. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    30
    1.6 Protocol Suites and Layering Models
    Physical Layer (Layer 1)
    specify details about the underlying transmission medium and hardware
    all specifications related to electrical properties, radio frequencies, and signals belong in layer 1
    Network Interface Layer (Layer 2)
    some publications use the term Data Link
    specify details about communication between higher layers of protocols (implemented in SW) and the underlying network (implemented in hardware)
    specifications about
    network addresses
    maximum packet size that a network can support
    protocols used to access the underlying medium
    and hardware addressing
  • 31. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    31
    1.6 Protocol Suites and Layering Models
    Internet Layer (Layer 3)
    Protocols in the Internet layer form the fundamental basis for the Internet
    Layer 3 protocols specify communication across the Internet (spanning multiple interconnected networks)
    Transport Layer (Layer 4)
    Provide for communication from an application program on one computer to an application program on another
    Includes specifications on
    controlling the maximum rate a receiver can accept data
    mechanisms to avoid network congestion
    techniques to insure that all data is received in the correct order
  • 32. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    32
    1.6 Protocol Suites and Layering Models
    Application Layer (Layer 5)
    specify how a pair of applications interact when they communicate
    specify details about
    the format and
    the meaning of messages that applications can exchange
    the procedures to be followed
    Some examples of network applications in layer 5
    email exchange
    file transfer
    web browsing
    telephone services
    and video teleconferencing
  • 33. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    33
    1.7 How Data Passes Through Layers
    Protocol implementations follow the layering model
    by passing the output from a protocol in one layer to the input of a protocol in the next
    To achieve efficiency
    rather than copy an entire packet
    a pair of protocols in adjacent layers pass a pointer to the packet
    Figure 1.2 illustrates layered protocols on the two computers
    Each computer contains a set of layered protocols
    When an application sends data
    it is placed in a packet, and the packet passes down through each layer of protocols
    Once it has passed through all layers of protocols on the sending computer
    the packet leaves the computer and is transmitted across the physical network
    When it reaches the receiving computer
    the packet passes up through the layers of protocols
    If the application on the receiver sends a response, the process is reversed
  • 34. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    34
    1.7 How Data Passes Through Layers
  • 35. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    35
    1.8 Headers and Layers
    Each layer of protocol software performs computations
    that insure the messages arrive as expected
    To perform such computation, protocol software on the two machines must exchange information
    each layer on the sender prepends extra information onto the packet
    the corresponding protocol layer on the receiver removes and uses the extra information
    Additional information added by a protocol is known as a header
    Headers are added by protocol software on the sending computer
    That is, the Transport layer prepends a header, and then the Internet layer prepends a header, and so on
    If we observe a packet traversing the network, the headers will appear in the order that Figure 1.3 illustrates
    Although the figure shows headers as the same size
    in practice headers are not of uniform size
    and a physical layer header is optional
  • 36. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    36
    1.8 Headers and Layers
  • 37. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    37
    1.9 ISO and the OSI Seven-Layer Reference Model
    At the same time the Internet protocols were being developed, two large standards bodies jointly formed an alternative reference model
    They also created a set of internetworking protocols
    These organizations are:
    International Standardization Organization (ISO)
    International Telecommunications Union,Telecommunication (ITU-T)
    The ITU was known as the Consultative Committee for International Telephone and Telegraph (CCITT)
    The ISO layering model is known as the Open Systems Interconnection (OSI) Seven-Layer Reference Model
    Figure 1.4 illustrates the seven layers in the model
  • 38. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    38
    1.9 ISO and the OSI Seven-Layer Reference Model
  • 39. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    39
    1.10 The Inside Scoop
    ISO and the ITU use a process that accommodates as many viewpoints as possible when creating a standard
    As a result, some standards can appear to have been designed by a committee making political compromises rather than by engineers and scientists
    The seven-layer reference model is controversial
    It did indeed start as a political compromise
    the model and the OSI protocols were designed as competitors for the Internet protocols
    ISO and the ITU are huge standards bodies that handle the world-wide telephone system and other global standards
    The Internet protocols and reference model were created by a small group of about a dozen researchers
    It is easy to see why the standards organizations might be confident that they could dictate a set of protocols and everyone would switch away from protocols designed by researchers
    At one point, even the U.S. government was convinced that TCP/IP should be replaced by OSI protocols
  • 40. © 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
    40
    1.10 The Inside Scoop
    Eventually, it became clear that TCP/IP technology was technically superior to OSI
    and efforts to develop and deploy OSI protocols were terminated
    Standards bodies were left with the seven-layer model
    Advocates for the seven-layer model have tried to stretch the definitions to match TCP/IP
    They argue that layer three could be considered an Internet layer and that a few support protocols might be placed into layers five and six
    Perhaps the most humorous part of the story is that many engineers still refer to applications as layer 7 protocols
    even when they know that layers five and six are unfilled and unnecessary
  • 41. Individual work #1 (10%)
    Get a copy from Pej Am SSIL 5th floor by 11.am
    Due 4.30pm today.
  • 42. Group Work #1 (10%)
    Next week-task will be given during the 1st hour of class time. Be there!
    Sit in Groups
    Short presentation
    Refer week 1 slides.
    Good luck!